Well perforating gun



Jan. 5, 1943. A. J. COLLINS 2,307,360

WELL PERFORATING GUN 1 Filed Dec. 9, 1940 2 Sheets-Sheet 1 &

3R k Rim 3 ammo/whom g- Auzhw JCd/ms Jam. 5, 194.3. A. J. COLLINS WELLPERFORATING GUN Filed Dec. 9, 1940 2 Sheets-Sheet 2 a vwq/rvbo'v lentoJan.

ascvsco were rirnr'onad arm Arthur .lT. Collins, Borpus sti, Tex.

Application December 9, 19%, Serial No. 369,147

it tllaims. (Cl. ltd-0.5)

invention relates to new and useful improvements in methods of and meansfor firing well perforating guns.

There are several types or perforating guns which are now commonly used,and are referred to as electrical guns and mechanical guns. In the heldtoday an electrical gun is the most commonly used, and a user of anelectrical gun has a certain degree of control over the firing of thegun which is not true of the present type of mechancal gun. However, anelectrical gun has numerous disadvantages. I'he electrical circuit ofthe gun may develop a short, thereby causing the gun to fireaccidentally, or it may he fired accidentally by static electricity setup in the gun while it is being run into the well casing. Thesedisadvantages make an electrical gun dangerous to run.

It is pointed out that a mechanical gun has numerous disadvantages also,such as the operator not having the degree of control over the firingmechanism that he has in an electrical gun. A mechanical gun is usuallyfired by dropping a go-devil through the rg tubing or along a wire lineso as to fall upon a trigger or the like and cause said trigger to firethe gun. The dropping of a go-devil oftentimes has its disadvantages assaid go-devil may hang up within the casing, thereby not permitting itto fall so as to trip said trigger; and also the mud within the tubingretards the downward travel of the godevil. it has often beenexperienced that when the gun did not fire, it was brought to thesurface, the go-devil becoming dislodged fell and fired the gun.

its can he seen, both an electrical and a mechanical gun may theaccidentally due to the laclr of control over the hiring mechanism; and,therefore, it is one object of this invention to provide an improvedmethod oi firing a gun whereby the gun is under the positive control oithe operator at all times and can not he accidentally fired.

an important object or the invention is to provide an improved method,of the character described, wherein agun equipped with mechanical firingmeans is lowered into the well and the firmeans is subjected to apressure fluid by holding it under restraint and the firing mens is thenreleased from the surface of the well whereby the pressure fluidoperates the firing means.

A further object of the invention is to provide an improved method ofactuating the firing elements of a perforating gun entirely by fluidpressure.

Another object of the invention is to provide an improved method offiring a perforating gun either by fluid pressure in the well bore or byan auxiliary pressure fluid introduced into the here of the gun.

A still further object of the invention is to provide an improved methodof firing a gun wherein the efficiency of the gun is not affected by thedepth of the well, but, to the contrary, the efficiency of the gun isincreased due to the fluid pressure within the well.

Another object of the invention is to provide an improved gun of thetype described, wherein the explosive charge is mechanicall detonated bymeans normally held in restraint and adapted to be impelled by apressure fluid when released.

Still another object or" the invention is to provide a gun of the typeset forth. wherein the mechanical detonating means, which is under nuidpressure, is released from the surface, thus providing definite controlthereof.

A further object of the invention is to provide an improved methodwherein the firin charge is mechanically detonated, and the mechanicalmeans is actuated by a pressure fluid.

A construction designed to carry out the invention will be hereinafterdescribed, together.

with other features of the invention.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawings,in which an example of the invention is shown, and wherein:

Figure 1 is a view, partly in elevation and partly in section, of a gunconstructed in accordance with the invention and adapted to carry outthe method, and

Figure 2 is a view, similar to Figure 1, show ing the gun after it hasbeen fired,

Figure 3 is a horizontal cross-sectional view taken on the line 3-3! ofFigure 1,

Figure 4 is a horizontal cross sectional View taken on the line t-t ofFigure 1,

Figure 5 is a horizontal cross-sectional view taken on the line 5-5 ofFigure 1,

Figure 6 is a horizontal cross-sectional view; taken on the line 6-6 ofFigure 1, and v Figure 7 'is an enlarged vertical view; partly in.section and partly in elevation, showing the;

detonating and percussion caps.

In. the drawings, the numeral? designates a sectional gun. The gun has ahead A at its.- upper end which forms its upper section, and-a firingportion B at its lower end which iormsits lower section. The head Aincludes a tubular sleeve H at its upper end, and the sleeve is providedwith a bore l2 extending therethrough. The lower end of the bore I2 iscounterbored to form a shoulder 13. Below the shoulder l3, the bore isenlarged to provide a lower shoulder l4, and the enlarged portion belowthe shoulder I4 is internally screw-threaded. The exterior of the sleeveH is provided with a plurality of inwardly-extending vertical recessesl5 adapted to receive dogs I6. The dogs are forced outwardly beyond thesurface of the sleeve by an upright flat spring I! disposed within therecesses. A collar I8 lie around the lower end of the recesses I5 and isembedded within the sleeve H. A similar collar l8 lies around the upperend of said recesses and is also embedded within the sleeve. The ends ofthe dogs underlie the collars, thereby the collars retain the dogs andthe springs 11 are urging the dogs outwardly at all times.

A sleeve I9 is provided with an upstanding screw-threaded pin on itsupper end which is screwed into the enlarged portion of the sleeve I Iso as to abut the shoulder I l. The sleeve I9 is provided with a bore 2|which is enlarged and tapered outwardly at its upper end to form a bowl22 and a shoulder 23 at the lower end of said bowl. Below the shoulder23, the bore is further enlarged to form a shoulder 24. A ring 25 abutsthe lower end of the sleeve l9, and has an annular upstanding neck 26provided on its periphery. A plurality of balls 21 lie between theupstanding neck and the inner periphery of the sleeve I!) so as torotatably lock the neck and sleeve together. It is pointed out that theballs 'are inserted through an opening 21' in the sleeve IS in the usualmanner. The ring 25 carries a plurality of depending rods 28 which aresecurely fastened to the ring 25. It is pointed out that the ring 25 andthe upstanding neck 26 are free to rotate in relation to the sleeve Hi.The lower ends of the rods 28 are each cut on its inner side so as toform a wedge 30.

A mandrel 3 I extends through the head A and has its upper end connectedto the tubing, or other suitable means, upon which the device is runinto the well. The lower end of the mandrel is provided with internalscrew threads 32 to which is connected a choke 33. The mandrel is alsoprovided with external screw threads 34. A

portion 35 of the outer surface of the mandrel 3| is provided with screwthreads which are of sawtooth or ratchet cross-section. Surrounding themandrel 3|, and engaging within the bowl 22 of the sleeve [9, is a splitnut 36 which has its outer surface tapered correspondingly to the bowl22, i

and its inner surface screw-threaded to mate with the screw threads 35of the mandrel 3|.

In order to hold the nut aganist rotation, a key 31, embedded in thebowl, engages in the split or gap of said nut. Thus the construction ofthe teeth of the mandrel and the bowl are so as to permit the mandrel tobe moved upwardly through said nut. The nut is elevated in the bowlsufllciently to permit the nut to expand, thereby allowing the threadsto pass each other. When the nut is moved upwardly into the enlargedportion of the bowl 22, it will be free and may spread so that thethreads will not be in constant engagement and will not act to screwsaid mandrel downwardly; but, as the threads engage, the nut will spreadand snap over the threads of the.

mandrel. However,.when the nut is down within the lower portion of thebowl 22, the threads will act so as to screw the mandrel downwardly whenthe mandrel is rotated. This is clearly brought out in my co-pendingapplication, Serial No. 318,050, filed February 9, 1940.

A sleeve 36, having a bore 39, is attached to the lower end of themandrel 3| by means of the screw threads 34 which mate with the screwthreads of the bore 39 within the sleeve 38. The bore 36 is decreased insize so as to form an orifice 40. Below the orifice 40, the bore isagain enlarged greater than that portion above the orifice, so as toform an annular shoulder 4|. The sleeve 39 is provided with a pluralityof downwardly-directed openings 42 through which the rods 26 may pass(Figure 1). At a point below the shoulder 4|, there is provided aninwardlydirected annular flange 43. The lower portion of the flange 43forms a shoulder 45, and the sleeve below the shoulder is internallyscrew-threaded at 46.

A cylinder block 41 is connected to the sleeve 36 by means of the screwthreads 46. The block is provided with an axial bore 48 extendingtherethrough. The upper end of said block is countersunk to form anannular recess 49 surrounding the bore 48. It is pointed out that therecess does not come in contact wtih the shoulder of the flange 43.Disposed between the shoulder and the recess is an annular ring 5|]which is securely held in place by the shoulder 45 and the bottom of therecess 49. A plurality of arms 5| are pivotally connected to the ring50, and are provided with a roller 52 at their upper ends. Aninwardly-directed lug 53, carrying a roller 53', is provided on each ofsaid arms below the roller 52 and above the ring 50. .It is pointed outthat the arms are always in alinement with the rods 28 and the openings42.

A piston or hammer 54 has a tight sliding fit within the axial bore 48of the block 41, and is provided near its upper end with a plurality ofrecesses 55 so that when the hammer is in the position shown in Figure1, the rollers 53 may enter said recesses and hold the hammer in saidposition, due to the fact that the rods 28 are urging the arms 50inwardly. Below the recesses 55, the hammer is provided with a pluralityof packing rings 56, so that fluid from the bore 39 may not flowdownwardly past the hammer. The sleeve 33, above the orifice 40, isprovided with a plurality of. openings 51 which establish communicationbetween the bore 39 and the exterior of the sleeve 38. The lower end ofthe block 41 is reduced to form a. shoulder 58, and the portion belowthe shoulder is externally screw-threaded. Attached to the lower end ofthe block 41 is a sub 59. The sub has its upper end countersunk I andinternally screw-threaded so as to mate with the lower end of the block41, and the central portion of the countersunk portion of the sub 59 isfurther countersunk so as to form a recess 60. Depending downwardly fromthe recess 60 is a plurality of longitudinal openings 6 I, and lying inbetween the lower ends of the openings BI is a guide member 62.

A piston 63 is slidable within the countersunk circumference reduced toform a. shoulder t1, and

1 is provided with an enlarged recess 68 on its bottom. Slidable withinthe recess 68 is an initial firing means 69 which contains a pair ofcartridges 'lll that are in axial alinement with the openings 6|. A gunbarrel H is attached to the lower end of the sub 59. As will be seen inthe drawings, the upper end of the barrel is provided with a countersunkportion-12, and is internally screw-threaded so as to confine theinitial firing charge within the recess 66. The barrel is preferablycylindrical in shape, and is provided with a plurality of elongatetransverse recesses or firing chambers 13 extending inwardly toward thecenter of said barrel. It is pointed out that the chambers arepreferably cylindrical in crosssection, and constitute a plurality offiring chamhere so that cartridges or explosive charges may be insertedtherein. An axial channel it extends throughout the barrel ll, and is sodisposed as to underlie the cartridges it. The lower end of the barrelis reduced and internally screwthreaded so as to receive a collar lwhich is at tached thereto. A sleeve it surrounds the gun barrel H, andis suitably paclred ofi so as to prevent moisture from entering saidbarrel. The lower end of the collar i5 is reduced and receives a,retaining collar ll. The collar ll abuts the lower end of the sleeve iiiand acts to retain the same on said barrel.

In the operation of the gun herein described, the gun is lowered intothe well by means of a tubing, or other suitable means, which isconnected to the upper end of the mandrel it. When the point at which itis desired to perforate has been reached, the tubing is rotated. In theusual case the well has a certain amount of fluid within the casing ill,but the amount of fluid is not sufficient to flow to the top of thewell. In some instances, it may be desired to shoot a well which i9 isflowing for various reasons; however, when the stratum or point has beenreached at which the casing id is desired to be perforated, as abovestated, the pipe is rotated which will rotate the mandrel ill. The dogsit, being in engagement with the casing '58, will not allow the head Ato rotate. However, the portion B of the gun will rotate due to the factthat the lower end of the mandrel iii is connected therewith.

The rods 29, being within the openings M, will rotate with the portionB, and the ring 25 and the upstanding neck it will also rotate with theportion B. As the mandrel ii is rotated, the head A will not be rotatedbut will remain stationary. The mandrel will be fed through the nut itdue to the fact that the pipe is lowered as it is rotated, therebylowering the portion B away from the portion A and withdrawing the rodsit out of the openings 32 until said rods have reached the positionshown in Figure 2. At this time the arms bl are free to pivot outwardly,thereby releasing the hammer 5d. The hammer has a tight sliding fitwithin the bore it of the block ti and therefore will not readily fall.Pressure exerted by the fluid within the casing is free to enter throughthe ports ii and act upon the top of the hammer it, thereby causing thehammer to move downwardly and strike the piston tit, which will also becarried downwardly. The pins M will strike the cartridges it, therebyexploding the same, and the flame of the explosion will be conducteddown through the channel it to the cartridges within the chamber it. Thefiring may be accomplished by pins or a tire train as is disclosed inmy"copendlng applicaspring I56 is of suflicient strength to hold thehammer upwardly, together with the piston 63, so that the cartridges 10may not be discharged until pressure is applied to the top of thehammer. Thus, as will be seen, this gun depends upon pressure actingupon the' top of the hammer 54 to fire the same.

In some instances, there is not enough fiuid within the casing 18 toapply sufilcient pressure to the top of the hammer. In this case, theports 51 may be left out of the gun or suitably blocked by a sleeve (notshown), or in any other suitable manner. Fluid may then be pumped downthrough the tubing and through the mandrel 3| so that it will act uponthe top of the hammer 5t. Thus the gun cannot be accidently fired due tothe fact that pressure is required to fire the gun and the atmosphericpressure under which the gun is assembled is not sufiicient to fire saidgun.

It is further pointed out that as the gun is lowered farther into thewell, there will be more fluid above the hammer M. In this manner therewill be a hydrostatic pressure built up above the hammer and, in theinstance where pressure is introduced into the tubing, there will bebuilt up a hydrostatic pressure within the tubing. In many instances,where there is not a sufiicient amount of fluid within the casing 18 tofire the gun, auxiliary fluid may be introduced into the casing so as tobuild up a hydrostatic head to fire the gun. This particular method offiring a gun by pressure can be applied to various guns and is notlimited to the structure herein disclosed; however, the structureillustrated may be used to perform the method of this invention andeliminates disadvantages of guns now in common use.

Various changes, alterations and modifications may be made in the size,shape and arrangement of the herein described elements, within the scopeof the appended claims.

What I claim and desire to secure by Letters Patent is:

1. A well bore perforating apparatus composed of a gun having acartridge carrying member, spring tensioned means in the member to firethe cartridge, a hammer slidably within the member, means to latch thehammer at points spaced from the firing means, means for unlatching thehammer, and means for supplying fluid pressure to the member to actupon. the hammer thereby tocause same to actuate the firing means.

2. A well bore perforating apparatus in accordance with claim 1, whereinthe spring means is of a strength to resist operation of the firingmeans upon the hammer moving into engagement therewith when not underthe influence of the fluid pressure.

3. A well bore perforating apparatus including an upper memberreceivable in the casing, means carried by the member and engageablewith the casing to hold the member against rotation, a lower member, arotatable mandrel extending through the upper member and into the lowermember, means which upon rotation of the man drel efiects slidingmovement of the lower member away from the upper member and while thelatter remains stationary, cartridge firing means in the lower member, aslidable hammer in the lower member for actuating the firing means,means for releasably holding the hammer inoperative, means havingconnection with the upper member for releasing the means which holds thehammer inoperative, and means for conveying fluid pressure into thelower member to act upon the hammer thereby to move same to cartridgefiring position.

4. A well bore perforating apparatus in accordance with claim 3, whereinthe means to releasably hold the hammer inoperative consists of pivotedlatches and wherein the means to release the hammer holding meansconsists of rods having connection with the upper member to partake ofthe sliding movement thereof and slidably connected to the lower member,to move the latches to unlatched position thereby to release' thehammer.

5. A well bore perforating apparatus composed of a gun having acartridge carrying member, a second member, a rotatable mandrelconnecting the members, a hammer for firing the charge carried by one ofthe members, means to latch the hammer spaced from the firing means,means carried by the other member for efiecting release of the latchingmeans, means operable by the mandrel to move the members toward eachother upon rotation of the mandrel, and means to actuate the hammer tofire the charge upon release of the latching means from the hammer.

6. A well bore perforating apparatus in accordance with claim 5, whereinthe means to release the latching means is slidably mounted in the othermember.

'7. A perforating gun firing apparatus includmg, a suspending mandrel, anon-rotatable memasoaaeo means carried by the rotatable member forholding the means inoperative, and means for releasing the latch meansactuated by the rotation of the mandrel and the rotatable member.

8. A perforating gun firing apparatus set forth in claim 7 wherein therotatable member is provided with inlets for the well fluid, and meansfor conducting the admitted well fluid to the firing means.

9. In a well gun firing device, the combination of a gun barrel, 9.support having means for connecting with said gun barrel and providedwith a chamber, a firing hammer disposed and slidable within saidchamber above the gun barrel, latch means carried by the support forholding the hammer in its inoperative position, rotatable means forunlocking said hammer, and fluid means for applying fluid pressure so asto actuate said hammer.

10. The method of firing a well bore perforating gun having an explosiveresponsive media for perforating the well bore and also having firingmeans to fire the explosive by impact, whichresides in disposing themedia substantially transversely of the longitudinal axis of the gun,holding the firing means at a point spaced above the media underrestraint by engagement therewith to resist actuation thereof, loweringthe gun into the well bore to be perforated, re-

her carried by said mandrel, a rotatable member carried by said mandrel,fluid actuated firing means carried by the rotatable member, latchleasing the firing means to free the same from restraint when the pointof firing in the well bore is reached, and constantly subjecting thefiring means to fluid pressure throughout the period of restraint toimpact the same against the explosive by movement of said firing meansaxially of said gun so as to fire the explosive and thereby dischargethe media to perforate said well bore.

ARTHUR J. COLLINS.

